fix

langs/cpp/Dockerfile

@@ -1 +1 @@
-RUN apt-get install gcc -y
+RUN apt-get install gcc g++ -y

langs/cpp/run.sh

@@ -2,6 +2,6 @@ OUT="$(mktemp)"
 
 g++ -o "$OUT" -xc++ -
 
-if [ -f $OUT ]; then
+if [ -f $OUT ]; && ! [ -s $OUT ]; then
   exec "$OUT"
 fi